1. Combine pork, garlic, ginger, onion, gochujang, chili flakes, soy sauce, mirin, and sesame oil together in a large mixing bowl. Fork the mixture to combine and ensure even distribution. Cover and refrigerate for at least an hour.
2. Heat a large frying pan over medium heat, drizzle in vegetable oil. Spoon in pork mixture, break up with a wooden spoon, and fry for 8-10 minutes until pork begins to brown.
3. Finely chop radishes and cucumber and put into a bowl along with a dash of salt and rice wine vinegar. (If pork was frozen, make sure it is defrosted and reheated before doing this). Toss pickles together, then set aside. Slice the base off each head of little gem, then snap off the leaves. Arrange lettuce leaves on a serving board.
4. Drizzle pork with honey and cook for 2 minutes until sticky. Spoon into prepared lettuce leaves, top with some pickled radish and cucumber, then sprinkle with toasted sesame seeds to serve.